This sounds like a classic many to many relationship. Correct me if I am wrong, but it sounds like you need to link many different employee records to the same project record but also need to link many different projects to the same employee record.
If so, you need these tables and relationships:
Employees::__pkEmployeeID = Employee_Project::_fkEmployeeID
Projects::__pkProjectID = Employee_Project::_fkEmployeeID
For an explanation of the notation that I am using, see the first post of: Common Forum Relationship and Field Notations Explained
With this set up, you can place a portal to Employee_Project on your Projects layout and set up Employee_Project::_fkEmployeeID as a drop down list of EmployeeID's and names to use to select employees for a given project. You are then creating new records in the Employee_Project table instead of the Employee table when you select your employees.
Sounds exactly like what I need. Thanks Phil, I'll work away on that and post if I've got any further questions.